PSI - Issue 71

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ScienceDirect

Procedia Structural Integrity 71 (2025) 134–141

Keywords: Abutment; Bending Stress; Flange Fracture; Pinion Head Gear; Tapered Roller Bearing. 1. Introduction Tapered roller bearings (TRB) can be put up to a combination of radial and thrust loads (Harris and Kotzalas, 2006). The load-carrying capacity of tapered roller bearings is greater than that of ball bearings due to line contact between races and rolling elements. The contact angle is designed based on the amount of thrust load to be supported in the application. In operation, the rollers are pushed against the guiding flange, and this condition limits the maximum operating speed for which TRB can be used. The differential system is crucial for an automobile as it transmits engine power to the rear wheel while facilitating the speed difference during execution of a turn. The pinion and crown gear arrangement distribute power from the engine through the propeller shaft to the wheels. Taper roller bearings are a popular choice for differential systems for precisely supporting the rotary elements such as crown gear, pinion gear, and drive shafts. ∗ Corresponding author. E-mail address: ninad.pawar@nbcbearings.in 5 th International Structural IntegrityConference & Exhibition (SICE 2024) Failure Analysis and Toughness Improvement for a Pinion Head Tapered Roller Bearing in Differential System of a Commercial Vehicle Ninad Vasant Pawar*, Aditya Mishra, Sandeep Saraf a Materials and Processing Technology, R&D, NBC Bearings (National Engineering Industries), Jaipur 302006 India. Abstract Tapered roller bearings are utilized in applications where operating loads are high with simultaneous radial and axial type of loads. A failure case was reported in pinion gear of commercial vehicle application where bearing cone was observed fractured at groove area in multiple locations. The subjected bearing cone was made of SAE 52100 material and surface treated with patented life improvement treatment for improved wear and fatigue resistance with longer service life. Fracture analysis through scanning electron microscopy (SEM) revealed multi-point fracture initiation from groove area causing the fracture to initiate and propagate towards larger face of bearing cone, ultimately causing flange separation and bearing failure. The fracture was observed taking place under bending stress. No material or heat treatment non-conformity was observed in metallurgical and fracture analysis. Further analysis revealed that the bearing cone which was fitted against pinion gear of differential system has discontinuous support due to roots of gear tooth causing cantilever loaded condition. The abutment available, material and surface treatment selection proved inadequate for given application conditions and more toughness was essential for bearing flange to operate in service. As a countermeasure, low carbon steel with case carburizing heat treatment was proposed for the bearing. The improvement in fracture load capacity of the low carbon steel bearing cone was compared with existing 52100 steel bearing cone with help of specially designed fixture on universal testing machine. The new bearing with low carbon steel with case carburizing treatment showed higher fracture loads for flange as compared to bearing made from SAE 52100 steel. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SICE 2024 organizers

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SICE 2024 organizers 10.1016/j.prostr.2025.08.019